"Did you take all of that down?"
It was held in a very recent Court of Appeal decision that for an agreement to be 'evidenced in writing', generally, all of the agreement, not just part of it, must be evidenced in writing.
The Legislation
Under the Housing Grants, Construction and Regeneration Act 1996 ("the Act") all parties to a construction contract (with certain defined exceptions) have a right to refer a dispute to adjudication. But; that is only construction contracts that are agreements in writing.
Section 107(2) of the Act reads as follows:-
"There is an agreement in writing –
(a) if the agreement is made in writing (whether or not it is signed by the parties),
(b) if the agreement is made by exchange of communications in writing, or